Can someone clear this up for me??
 

Hi fellas

I know this has probably been covered a lot but I'm just looking at my own confirmation... I have a 53 Blob WRX and I am thinking about fitting a VTA dump valve but have heard mixed reviews varying from yes its fine to no it will ruin the engine, etc, etc so what I am asking is...what is the right answer?

do it mate, imagine how cool you will look when changing gear, also fit a wrc sticker kit then join sioc on Facebook!

the right answer is it will make your engine run a bit rich as the ecu adds extra fuel for the metered amount of air but it gets dumped into the atmosphere with a VTA whereby a standard valve will redirect that air back to be consumed by the engine. does it damage your engine? who knows, ive yet to see any proof from anyone that their engine blew up from having one fitted and the doom merchants will say it will but put it this way andy forrest mapped my wagon with one fitted and if it was the engine killer some would have people believe then surely top tuners like andy f would refuse to map cars with them fitted for fear of engine failures and getting the blame? its up to you bud but my wagon ran 315 bhp with one fitted and i know the guy who bought it and it still runs sweet as a nut. worst case scenario: your engine will blow up (apparently) more likely scenario: you will use a bit more fuel as it will run slightly rich and will make a nice wooshing sound when it vents. you choose :D

Well said yabbadoo4, ideally you need a remap as i have one and have not remapped my car yet and i can tell its over fueling so i'm going to swap back standard Rcv until i get it remapped

It's been covered above but.

Pros: Wooshing noise to impress your friends
Cons: Higher fuel consumption, loss in power

With a remap you won't lose anything so I'd budget that in too.

Cheers mate very helpful, will give it some thought, have heard a few scoobs with a VTA and it is something I am quite fond of so when I come round to mapping I will speak to the mapper first and go from there :)

Your sarcasm knows no bounds! Gratefully received and acknowledged

Depends how technically you want to look at it. There are pros and cons for all 3 set ups and some DV's have compromises such as spring tension adjustment and plumb back features.

I've asked many questions about BOV's and never had them all answered or answer satisfactorily.

At the moment I'm trying to understand a blanked DV/DV's effect in regards to lift-off det, actuator vac pressure and cylinder cooling.

I still can't fathom as to why a blanked DV causes rich running as the unused air goes to to the same place a recirc dumps air thus creating enough pressure to stop fresh air passing the MAF.

All I say in regards to BOV's is get a 2 way one that can partially or fully recirc (if needed) that comes with a adjustable spring tension, that way you can have any set up you want with a slight control on how many revs it takes to make that much maligned piissshhh sound.

I currently run a GFB VTA with the spring tension set to hardest which means I don't really Vent to air unless I'm giving it the beans, around town unused air heads back through the turbo giving a gentle and mildly pleasing chatter sound.

Don't be swayed by what your fellow Subaru owners think as girls and lesser car owners love the sound of a BOV!

Pros: None. The wooshing noise makes you look a d*ck:D

Cons: increased fuel consumption, over-rich running leading to borewash, oil dilution, possibly cat damage, and possibly burnt valves. Possible lumpy running on gearchange unless mapped out.

Your car, your choice.

So I guess we have come to the conclusion that everyone with a dump valve fitted to their scoob is a dick.

just open the window, change gear and yell VWWWWWWT-SHHHHHH, it'll be less risky

way ahead of you...should have seen me down the dual carriageway yesterday.....burberry cap on, fake gold.... shouting psssssssssst out the window to all the other peasant vehicles

HKS SQV does sound cool though.

It's true. I have an HKS gay valve on my car and I'm a complete dick!

I agree an exhaust system + bov goes together nicely on a subaru IMO, each to their own...

Would a remap prevent all of the problems associated with an atmospheric dump valve?

Yes, you can map the car for one. Mine is.

No chance of borewash, rough running or any of that crap by mapping it in?

You just compensate for it in the map so can get the car running perfect.

that is good news :) don't know if I want to part with £245 for an hks ssqv though didn't realise they cost so much :(

LOL:norty::lol1::norty:

Think rough running is probably from a cheap DV with a suspect spring, I had bore wash in my WRX and I asked the tuner who diagnosed the problem if it was because of the VTA DV and he laughed then said "No."

The folks who slag VTA's off are the same people who have a pop and bang map. I'm not sure which set up uses more fuel on the over run though.

I have a second hand SSQV you can fit :P

How much?